Automatic lash adjuster



Nov. 27, 1956 c, SAMPIETRO 2,771,866

AUTOMATIC LASH ADJUSTER Filed July 2, 1954 7 I III IR 111 I -2 4 Z4 it 44 w I41 FE 27 21 7- Ad Add lies Char/e6 Sazzzpie fro k: M g @u/kgg- H AUTOMATIC LASH ADJUSTER Achilles Charles Sampietro, Ann Arbor, Mich., assignor to Thompson Products, Inc., Cleveland, Ohio, a corporation of Ohio Application July 2, 1954, Serial No. 440,896

14 Claims. (Cl. 123-90) This invention relates to a lash adjuster for engine valve linkages which will not add to the reciprocating weight or inertia of the linkage.

Specifically this invention deals with an oil actuated automatic valve lash adjuster on the pivot post of the rocker arm of a valve in head engine valve linkage.

According to this invention a light Weight stamped, cast, brazed, or otherwise fabricated metal rocker arm having a fragmental spherical depressed pivot portion, receives a mounting stud or post anchored in the engine head in communication with the oil gallery. A hearing member with a hemispherical end is slidable on the post or stud to seat the depressed portion of the rocker arm. The stud or post has an oil passage therethrough communicating with the interior of the bearing member. A check valve accommodates flow of oil from the gallery to the bearing member but prevents reverse flow of oil. The bearing member is thus urged by oil pressure into good bearing contact with the depressed portion of the rocker and the rocker in turn is urged into good bearing contact with the conventional push rod and spring loaded engine valve. A leak down of oil is permitted from the bearing member to prevent overloading of the bearing which might interfere with proper seating of the engine valve.

A feature of this invention is the provision of an automatic lash adjuster which does not add to the reciprocating weight of the valve gear.

Another feature of the invention is to provide an auto matic valve lash adjuster which is not subject to the violent accelerations and wear encountered by the conventional reciprocating adjusters.

An important feature of the invention is the provision of a combined lash adjuster and pivot post for a rocker arm.

An object of the invention is to provide an inexpensive oil actuated lash adjuster on the pivot post of a rocker arm.

A further object of the invention is to provide a nonreciprocating oil operated lash adjuster for valve gears.

A still further object of the invention is to provide a combined rocker arm support and lash adjuster.

A still further object of this invention is to provide a lash adjuster which is fed directly from the oil gallery of a valve in head engine to urge the rocker arm of the valve gear into zero lash contact with the push rod and engine valve.

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheet of drawings which, by way of preferred example only, illustrates one embodiment of the invention.

Figure 1 is a transverse cross-sectional view, with parts in elevation, of a valve in head internal combustion engine equipped with an automatic lash adjuster according to this invention;

Figure 2 is a plan view along the line II-II of Figure 1;

nited States Patent F 2,771,866 Patented Nov. 27, 1956 Figure 3 is a horizontal cross-sectional view taken substantially along the line III-III of Figure 1; and

Figure 4 is a fragmentary view similar to Figure l but illustrating a modified check valve arrangement for the lash adjuster.

As shown on the drawings:

In Figure 1, the internal combustion engine 10 includes a cylinder block 11 and a cylinder head 12. The head 12 has a guide 13 receiving in slidable relation therein the stem 14 of a poppet valve 15. The head 16 of the valve 15 cooperates with a seat 17 in the engine head 12 to control flow between the valve port 18 in the head 12 and the combustion chamber 19. The upper end of the valve stem has grooves 20 therearound and the conventional split valve locks 21 have beads seated in these grooves. A valve spring retainer 22 is fixedly held on the upper end of the valve stem by the locks 21 and a valve spring 23 surrounding the valve stem has one end bottomed on the retainer 22 and the other end bottomed on a shoulder 24 of the engine head 12 surrounding the guide 13. The valve spring 23 is compressed to hold the valve head 16 against its seat 17. A stamped sheet metal rocker arm 25 has a depressed fragmental spherical socket portion 26 in the bottom thereof with an aperture 27 through the bottom of the socket.

The rocker arm 25 as indicated in Figure 2 is bounded by an upturned peripheral flange 28 to have a generally bowl-shaped interior 29.

On one side of the socket 26, the bottom of the bowl 29 is raised to provide an inverted socket 319 for the rounded end 31 of a push rod 32. The push rod end 31 can rock in the socket 30 and an oil aperture 33 is provided through the socket 30 to lubricate the end 31 of the push rod.

On the opposite side of the socket 26 the bowl-shaped bottom portion 29 of the rocker 25 is depressed at 34 to provide a rounded exterior for rocking on the end 35 of the valve stem 14.

In accordance with this invention the rocker arm is mounted on the engine valve head 12 by means of an automatic lash adjuster 36.

The lash adjuster 36 includes a tension bolt or post 37 with a hollow shank 38 and a socket head 39. The shank has a threaded end 38a threaded into a boss 40 of the engine valve head 12 to place the passageway 41 of the shank in communication with the oil gallery 42 of the engine head. As is customary this oil gallery 42 receives oil under pressure from the lubricating system (not shown) of the engine 10.

The shank 38 of the post 37 fits freely in the aperture 27 and projects into the bowl portion 29 of the rocker arm 25. Radial passages 43 are provided through the shank 38 immediately under the head 39. An annular groove 44 surrounds the shank and communicates with the passages 43. A synthetic rubber or other elastic ring 45 is seated in the groove 44 to control oil flow, as will be hereinafter more fully described.

A bearing member or ball 46 has a cylindrical bore 47 slidably receiving the shank 38. The member 46 has a fragmental spherical end 48 sized to fit the socket 26 of the rocker for tiltably mounting the rocker. A cylindrical extension 49 on the ball end 48 cooperates therewith to define a chamber 50 surrounding the upper end of the stud shank 38. The head 39 of the stud or post has a circular periphery 51 of smaller diameter than the interior wall 52 of the cylindrical extension 49 to provide an annular leakage path 53 between the head 39 and the cylindrical extension 40.

The central portion of the area of the shank 38 embraced by the cylindrical bore of the ball member or bearing member 46 is provided with a-groove 54 into which 3 is seated a seal ring or packing ring 55 to control oil leakage from the chamber 50.

In operation, oil from the gallery 42 flows through the passages 41 and 4-3 to unseat therubber ring 45 from the bottom of the groove 44 thereby accommodating fioW of oil into the chamber 58. Oil under pressure in this chamber will act on the head end of the ball or bearing member 46 to seat the spherical face 48 thereof into good bearing engagement with the socket 26 of the rocker arm. The rocker arm is thereby urged into good contact with the end 31 of the push rod and the end 35 of the valve stem to take up lash or play in the valve gear. In order to insure full and complete seating of the valve head 16, the leakage path 53 from the oil chamber 59 will prevent an undue building up of pressure in the chamber. The load exerted by the oil pressure in the chamber 50 on the bearing 46 is'always less than'the load exerted by the valve spring 23 in the closed position of the valve.

Oil issuing from the leakage path 53 will flow into the bowl bottom of the rocker arm 25 to lubricate the bearing head 48 in the socket wall 26. Sufiicient oil is also available in the bowl-shaped bottom of the rocker arm to fiow through the passage 33 to lubricate the push rod end 31. The seal ring 55 is effective to prevent leakage of oil through the cylindrical bore 47 of the bearing member 46.

The elastic ring valve 45 accommodates on way flow of oil from the passages 43 into the chamber 30 but prevents back flow of oil.

The ring check valve arrangement 45 can be replaced with a spring pressed ball member 56 coacting with a seat 57 at the end of the passage 4 As shown in Figure 4 the bail and spring are inserted in a counterbore 58 formed in the end of the bore 41 and through the head 39. The spring is compressed by a plug 59 closing the top of the counterbore 58 and pressed or screwed therein.

From the above descriptions it will therefore be understood that this invention provides an automatic valve lash adjuster which does not add to the inertia or reciprocating weight of the valve gear and which serves the dual function of not only taking up lash in the valve gear but also providing a pivot support for the rocker arm of the valve gear.

It will be understood that modifications and variations may be effected Without departing from the scope of the novel concepts of the present invention.

1 claim as my invention:

1. An automatic valve lash adjuster for a rocker arm, push rod and engine valve assembly, which comprises a post adapted to receive oil therethrough from the engine gallery, a bearing slidable on and disposed around said post and coacting therewith to define a trapped oil chamber therebetween, said bearing having a head seatingthe rocker arm, a check valve on the post trapping oil in said chamber, means providing a leak-down path from the chamber, and oil from said post urging the bearing against.

the rocker arm to maintain the rocker arm in working contact with push rod and engine valve.

2. An engine valve linkage which comprises a dished sheet metal rocker arm having an apertured depressed fragmental spherical socket portion in the bottom thereof, an inturned push rod receiving socket portion in said bottom on one side of the depressed socket portion and a valve stem engaging portion on said bottom on the other side of the depressed socket portion, a tension bolt having a shank extending freely through the depressed socket aperture and having a head above the bottom of the rocker arm, a bearing member having 'a ball'cnd seated in said depressed socket portion and slidably mounted on the bolt, said bearing member coacting with the head of the bolt to define an oil chamber and provide a leakage path from said chamber into the rocker arm, said bolt having a passage adapted'for receiving oil from the engine, check valve means in said passage accommodating oil flow into said chamber but checking reverse flow of oil, and'means controlling leakage of oil between the ball. member and the shank of the bolt whereby oil in said chamber is effective to urge the ball member against the depressed socket to hold the inturned push ro'cl'socke't and valve stem engaging portioniin good contact with the push rod and valve stem while leakage of oil from the chamber will permit full closing of the engine valve.

3. A combined automatic valve lash adjuster and rocker arm pivot which comprises a bolt having a hollow shank and a head on one end thereof, a groove around said shank adjacent said head, ports connecting the int'erior of the shank withthe groove, a resilient ring seated in said groove controlling flow out of said ports and checking reverse flow, a bearing member having a ball end slidably mounted on the-shank of the bolt and and a cylindrical end freely embracing the head of the bolt to cooperate therewith in defining a' chamber and leakage path from the chamber, and a rocker arm having a depressed fragrnental spherical apertured portion receiving the shank of the bolt freely .therethrough and rockably mounted on the ball end of the bearing member.

4. A combined rocker arm pivot and automatic valve lash adjuster which comprises a post member attachable to the oil gallery of an engine and having a passage there-- through for receiving oil therefrom, a bearing member said bearing member and post member having a leakdown path therebetween accommodating flow of oil from the chamber, and a rocker arm rockably mounted on the bearing member and held in operative relation by oil pressure urging the bearing member against the rocker arm.

5. In a post mounted engine valve rocker arm assembly of the type receiving oil from the engine gallery through the post, the improvement of a rocker bearing member disposed around and slidable on the post and receiving oil therefrom to be urged against the rocker arm by oil pressure for controlling lash in the assembly.

6. A post mounting for an engine valve rocker arm which comprises a bolt having a hollow shank adapted to be secured to the oil gallery of the engine to receive oil therefrom, a head on said shank, ports adjacent the head communication with the interior of the shank, a check valve controlling flow of oil from the ports, a rocker arm bearing slidable .on the shank and having a hollow portion embracing the head to cooperate with the bolt in defining a chamber receiving oil from the ports, oil in said chamber urging the bearing into seated engagement with a rocker arm on the post, and said head and bearing having an oil leakage path there-betweento bleed oil from the chamber.

7. In combination a rocker for transmitting motion between oppositely reciprocating elements, said rocker having an opening extending therethrough in the thrust direction, rocker supporting means including -a movable member journalling the rocker about one end of said opening, a fixed member extending through said opening and carrying a plunger in telescopic relation with said movable member, a support for said fixed member'on the opposite side of the rocker from said plunger, said movable member and plunger defining a fluid pressure chamber on the opposite side of the rocker from said support, and means for introducing fluid into said chamber and restricting its return therefrom.

8. The invention defined in claim 7, wherein said last named means "includes a source of oil under pressure withinsaid support, a passageway'in said fixed member connecting at one end with said source and at the other end withsaid' chamber, and a check valve controlling oil flow through'said passage and movable to its closedposition in response to chamber pressure.

9.1;: combination with a poppet valve actuatable rocker having an ope'ning extending therethr'ough in the thrust direction and a fixed support for the valve, 21' by draulic lash adjuster including a cylinder member and a plunger, said cylinder member having a bore and being provided adjacent one end of said bore with an external surface journaling the rocker for oscillatory movement, said plunger having a close fit in said bore and a reduced diameter portion extending through said opening and fixed to said support on the opposite side of the rocker from the cylinder member, sealing means interconnecting the cylinder member and said plunger reduced diameter portion opposite said one end of the bore, said sealing means being spaced axially from the plunger defining the rocker adjacent end of an oil pressure chamber, and means for introducing fiuid into the chamber and restricting its return therefrom.

10. The invention defined in claim 9, wherein said last named means includes a source of oil under pressure within said support, a first passageway extending longitudinally through said plunger reduced portion from said source, a second passage in said plunger interconnecting said first passageway and said chamber, and a check valve at the chamber end of said second passage and movable to close the same in response to chamber pressure.

11. In a journaling and lash take-up device for a rocker of a poppet valve operating linkage, a generally cupshaped member having its external end wall and adjacent side wall surfaces spherically curved and having its internal side wall surfaces defining a bore, said member having an openin in its end wall aligned with said bore, a plunger axially spaced from said end wall having a close fit in said bore and a stud portion of reduced diameter extending through said opening adapted to be fixedly secured adjacent its extended end, an annular seal between the cup-shaped member and the stud portion, and a check valve controlled passage extending endwise through the plunger accommodating one-way flow of fluid into the space between the plunger and said end wall.

12. In combination, a rocker of generally upwardly presenting channel-like shape having its bottom wall spherically depressed intermediate the ends to socketably receive a ball ended rocker journaling member, oppositely reciprocating elements terminating in end-abutting engagement withthe under surface of said bottom Wall adjacent the respective ends of the rocker, a fixed support below the rocker, a lash adjuster including a member of generally upward presenting cup shape having side walls defining a cylinder bore and terminating with an externally ball-shaped end wall journaling said spherically depressed rocker bottom wall, a plunger having a close fit in said bore and cooperating with said end wall in defining an oil pressure chamber, said" plunger having an aperture connecting said chamber with a source of lubricating oil, a ball check valve movable in said aperture in response to chamber pressure, said plunger having a reduced diameter stud portion extending through said chamber and fixed to said support, said end wall and rocker bottom Wall being apertured for passage of said stud portion, and means sealing the aperture in said end wall against escape of oil along said stud portion from the chamber.

13. In combination, a rocker of generally upwardly presenting channel-like shape having its bottom wall spherically depressed intermediate the ends to socketably receive a ball-ended rocker journaling member, oppositely reciprocating elements terminating in end-abutting engagement with the under surface of said bottom wall adjacent the respective ends of the rocker, a fixed support below the rocker having an oil gallery supplied With oil under pressure, a lash adjuster including a member of generally upwardly presenting cup shape having side walls defining a cylinder bore and terminating with an externally ball-shaped end wall journaling said spherically depressed rocker bottom wall, a plunger having a close fit in said bore and cooperating with said end wall in defining an oil pressure chamber, said plunger having an oil passage extending internally thereof from said chamber, a check valve movable into blocking relation with said passage under pressure from within the chamber, said plunger having a reduced diameter stud portion extending through said chamber and fixed to said support, said stud portion being provided with a passage connecting said oil gallery to said passage above the check valve, said end wall and rocker bottom wall being apertured for passage of said stud portion, and means sealing said end wall aperture to said stud portion whereby substantially all leakage from said chamber occurs between the surfaces of said plunger and cylinder bore from which it overflows into the space between the channel side walls of the rocker.

14. In a hydraulic lash adjusting device for a rocker of the type fulcrumed on a stud extending therethrough in the thrust direction, a cylinder member having a bore and an external surface at one end adapted to journal the rocker for pivotal movemenet about its fulcrum axis, a stud having a plunger portion fitting said bore, said cylinder member having an opening in its rocker journaling end for passage of the stud and having walls defining a chamber between said opening and said plunger portion, said opening and the adjacent periphery of the stud having a close sliding fit, and means for introducing fluid into said chamber and restricting its return therefrom.

References Cited in the file of this patent UNITED STATES PATENTS 1,937,932 Woolman Dec. 5, 1933 2,669,981 Leach Feb. 23, 1954 FOREIGN PATENTS 436,744 Great Britain Oct. 17, 1935 

